Modem vehicles are typically equipped with several independent electronic systems. For instance, most modern vehicles have a sound system and a security system. The sound system usually consists of an AM/FM radio, a cassette or CD (compact disk) player, an equalizer/amplifier, and speakers. The radio and player are arranged in a metal casing or housing that is mounted in a dashboard of the vehicle. The housing has a standardized size, often expressed in terms of DINs (Deutsche Industry Normen), to ensure that the sound system is compatible with and can be retrofit into most vehicle dashboards.
The security system is entirely separate from the sound system. The security system generally consists of security sensors placed throughout the vehicle, and a central application-specific integrated circuit (ASIC) to monitor the sensors and determine whether security is being jeopardized. Security System also controls actuators to lock/unlock doors or windows, and an alarm or siren.
Most late model vehicles are also constructed with a diagnostic system that analyzes performance of the vehicle's engine, transmission and fuel system, and other components (1996 or later for OBD II, 1993 or later for OBD I). The diagnostic system can be coupled to an external computer to download or monitor diagnostic information that is useful to a vehicle mechanic during servicing of the vehicle. Additionally, the diagnostic system might include dashboard displays that inform the driver of various operating conditions.
In some recent models, vehicles are being equipped with a navigation system that incorporates a global positioning system (GPS) receiver. The GPS receiver has an antenna to receive signals from a satellite network. The vehicle navigation system uses the satellite positioning signals to compute coordinates that locate the vehicle over the surface of the earth with regard to longitude, latitude, and altitude. Also, with the appropriate map software, the vehicle's location can then be shown on a map.
Cellular communications systems have also been added to vehicles. These communications systems enable the vehicle driver or occupant to transact telephone calls from their vehicle. Some of the more sophisticated systems are voice controlled which permit the driver to initiate or receive calls while traveling without removing a hand from the driving wheel, or diverting his/her eyes from the operation of the vehicle.
While these various electronics systems have proven useful to vehicle users, there is a drawback in that the systems are unrelated and incompatible. Each system employs separate proprietary dedicated processors or ASICs (application specific integrated circuits) which execute incompatible proprietary software. If a vehicle owner would like to add a security system to his/her vehicle, the owner must purchase an entire security system from one of the vendors and have it customarily installed. There is no way to add security functionality to an existing electronics system, such as the navigation system or the sound system.